cooperative transition
A transition that involves a simultaneous, collective displacement or change of state of the atoms and/or electrons in the entire system. Examples: An order–disorder transition of atoms or electrons, as in an alloy, a ferromagnet or superconductor; a Jahn–Teller or ferroic transition; a martensitic transition.
PAC, 1994, 66, 577. 'Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)' on page 580 (